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CORRECTION article

Front. Microbiol., 12 March 2019 | https://doi.org/10.3389/fmicb.2019.00425

Corrigendum: Genome-Based Genetic Tool Development for Bacillus methanolicus: Theta- and Rolling Circle-Replicating Plasmids for Inducible Gene Expression and Application to Methanol-Based Cadaverine Production

Marta Irla1, Tonje M. B. Heggeset2, Ingemar Nærdal2, Lidia Paul1, Tone Haugen2, Simone B. Le2, Trygve Brautaset2,3 and Volker F. Wendisch1*
  • 1Genetics of Prokaryotes, Faculty of Biology and CeBiTec, Bielefeld University, Bielefeld, Germany
  • 2SINTEF Materials and Chemistry, Department of Biotechnology and Nanomedicine, Trondheim, Norway
  • 3Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway

In the original article, there was a mistake in Table 2 as published. The cadaverine concentrations reported were miscalculated and overestimated by 41.6%, because the HPLC standard solution consisted of “cadaverine dihydrochloride (175.1 g/mol)” and not “cadaverine (102.18 g/mol).” The corrected Table 2 appears below.

TABLE 2
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Table 2. Fed-batch methanol fermentation production data of strains MGA3(pBV2mp-cadA) and MGA3 (pTH1mp-cadA).

Because of the error reported above, a correction has been made to the Abstract:

Bacillus methanolicus is a thermophilic methylotroph able to overproduce amino acids from methanol, a substrate not used for human or animal nutrition. Based on our previous RNA-seq analysis a mannitol inducible promoter and a putative mannitol activator gene mtlR were identified. The mannitol inducible promoter was applied for controlled gene expression using fluorescent reporter proteins and a flow cytometry analysis, and improved by changing the −35 promoter region and by co-expression of the mtlR regulator gene. For independent complementary gene expression control, the heterologous xylose-inducible system from B. megaterium was employed and a two-plasmid gene expression system was developed. Four different replicons for expression vectors were compared with respect to their copy number and stability. As an application example, methanol-based production of cadaverine was shown to be improved from 6.5 to 10.2 g/L when a heterologous lysine decarboxylase gene cadA was expressed from a theta-replicating rather than a rolling-circle replicating vector. The current work on inducible promoter systems and compatible theta- or rolling circle-replicating vectors is an important extension of the poorly developed B. methanolicus genetic toolbox, valuable for genetic engineering and further exploration of this bacterium.”

Additionally, a correction has been made to the Results, Cadaverine Production From Methanol by Expression of a Heterologous Lysine Decarboxylase Gene From a Theta-Replicating Plasmid:

“The plasmids pTH1mp and pBV2mp, containing the mdh promoter were used to study cadaverine production in B. methanolicus during fed-batch methanol fermentation. We have previously reported a methanol-based cadaverine production titer of 6.5 g/L by B. methanolicus MGA3 (pTH1mp-cadA), a strain overexpressing the lysine decarboxylase cadA gene from E. coli (corrigendum to Nærdal et al., 2015). We compared cadaverine production in the strain overexpressing cadA from a theta-replicating plasmid during high cell density fed-batch fermentation. The B. methanolicus strain MGA3 (pBV2mp-cadA) was tested in duplicates under comparable fermentation conditions. Samples for cadaverine and amino acid analysis, cell dry weight and OD600 were taken throughout the cultivation. As presented in Table 2, we obtained a cadaverine production titer of 10.2 g/L based on the alternative theta-replicating pBV2mp plasmid. A substantial 55% production increase compared to the previously reported (pTH1mp-cadA)-based strain was observed. While biomass and by-product levels were similar between the two strains, the specific growth rate of MGA3 (pBV2mp-cadA) was lower than that of MGA3 (pTH1mp-cadA) (Table 2).”

Lastly, in the original article, the reference for “(Nærdal et al., 2015)” was incorrectly written as “Nærdal, I., Pfeifenschneider, J., Brautaset, T., and Wendisch, V. F. (2015). Methanol-based cadaverine production by genetically engineered Bacillus methanolicus strains. Microb. Biotechnol. 8, 342–350. doi: 10.1111/1751-7915.12257”.

It should be “Nærdal, I., Pfeifenschneider, J., Brautaset, T., and Wendisch, V. F. (2015). Methanol-based cadaverine production by genetically engineered Bacillus methanolicus strains. Microb. Biotechnol. 8, 342–350. doi: 10.1111/1751-7915.12257. Microb. Biotechnol. 2019, 12, 182-183”.

The authors apologize for these errors and state that this does not change the scientific conclusions of the article in any way. The original article has been updated.

References

Nærdal, I., Pfeifenschneider, J., Brautaset, T., and Wendisch, V. F. (2015). Methanol-based cadaverine production by genetically engineered Bacillus methanolicus strains. Microb. Biotechnol. 8, 342–350. doi: 10.1111/1751-7915.12257. Microb. Biotechnol. 2019, 12, 182–183.

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Keywords: Bacillus methanolicus, thermophile, methylotroph, genetic tool box, theta-replicating plasmids, gene expression

Citation: Irla M, Heggeset TMB, Nærdal I, Paul L, Haugen T, Le SB, Brautaset T and Wendisch VF (2019) Corrigendum: Genome-Based Genetic Tool Development for Bacillus methanolicus: Theta- and Rolling Circle-Replicating Plasmids for Inducible Gene Expression and Application to Methanol-Based Cadaverine Production. Front. Microbiol. 10:425. doi: 10.3389/fmicb.2019.00425

Received: 21 January 2019; Accepted: 19 February 2019;
Published: 12 March 2019.

Edited and reviewed by: Kian Mau Goh, University of Technology Malaysia, Malaysia

Copyright © 2019 Irla, Heggeset, Nærdal, Paul, Haugen, Le, Brautaset and Wendisch. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Volker F. Wendisch, volker.wendisch@uni-bielefeld.de